Modify the Java code implemented in the Philosopher Class by using Sempahores, to allowing only four philosophers to eat at the same time. This concept can be easily implemented using a counting semaphore to limit the number of philosophers which can start taking chopsticks at the same time to four. This way, at least one philosopher will be able to eat, and later release the chopsticks, then allowing at least another to eat, etc.

public class Philosopher extends Thread {

private GraphicTable table;

private Chopstick left;

private Chopstick right;

private int ID;

final int timeThink_max = 5000;

final int timeNextFork = 100;

final int timeEat_max = 5000;

Philosopher(int ID, GraphicTable table, Chopstick left, Chopstick right) {

this.ID = ID;

this.table = table;

this.left = left;

this.right = right;

setName("Philosopher "+ID);

}

public void run() {

while(true){

// Tell the table GUI that I am thinking

table.isThinking(ID);

// Print to console that I am thinking

System.out.println(getName()+" thinks");

// Let the thread sleep (in order to simulate thinking time)

try {

sleep((long)(Math.random()*timeThink_max));

} catch(InterruptedException e) {

System.out.println(e);

}

// Done with thinking

System.out.println(getName()+" finished thinking");

// and now I am hungry!

System.out.println(getName()+" is hungry");

// Tell the GUI I am hungry...

table.isHungry(ID);

// Let's try to get the left chopstick

System.out.println(getName()+" wants left chopstick");

left.take();

// Tell the GUI that I took the left chopstick

table.takeChopstick(ID, left.getID());

System.out.println(getName()+" got left chopstick");

// I'll wait a bit before I try to get the next chopstick (it's philosopher's etiquette)

try {

sleep(timeNextFork);

} catch(InterruptedException e) {

System.out.println(e);

}

// Ok, enough etiquette nonesense, now I need my right chopstick

System.out.println(getName()+" wants right chopstick");

right.take();

// Got it!

table.takeChopstick(ID, right.getID());

System.out.println(getName()+" got right chopstick");

// Sweet taste of steamed rice....

System.out.println(getName()+" eats");

try {

sleep((long)(Math.random()*timeEat_max));

} catch(InterruptedException e) {

System.out.println(e);

}

// Ok, I am really full now

System.out.println(getName()+" finished eating");

// I just realized I did not wash these chopsticks

// and the philosopher on my right is coming down with a flu

// I'll release the left chopstick

table.releaseChopstick(ID, left.getID());

left.release();

System.out.println(getName()+" released left chopstick");

// I'll release the right chopstick

table.releaseChopstick(ID, right.getID());

right.release();

System.out.println(getName()+" released right chopstick");

}

}

}

public class Chopstick t private int ID; // hint: use a local variable to indicate whether the chopstick is free (lying on the table), e.g. private boolean free; private boolean free -true; Chopstick(int ID) { this.ID ID; synchronized void take() 1 if(!free) try this.wait(); J catch (InterruptedException e1) f // TODO Auto-generated catch block e1.printStackTrace(; free false synchronized void release() { free true; this.notify); public int getID( return(ID)